Fair value and gross unrealized losses of investment securities available-for-sale, aggregated by investment category and length of time individual securities have been in a continuous unrealized loss position (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	$ 128,277	$ 122,731
Less than 12 months Gross Unrealized Losses	655	884
12 months or more Fair Value	39,392	45,807
12 months or more Gross Unrealized Losses	2,516	6,831
Total Fair Value	167,669	168,538
Total Gross Unrealized Losses	3,171	7,715
US Government Sponsored Enterprises Debt Securities Member
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	31,912	0
Less than 12 months Gross Unrealized Losses	173	0
12 months or more Fair Value	0	0
12 months or more Gross Unrealized Losses	0	0
Total Fair Value	31,912	0
Total Gross Unrealized Losses	173	0
Obligations of Puerto Rico, States and political subdivisions
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	2,798	7,817
Less than 12 months Gross Unrealized Losses	34	28
12 months or more Fair Value	0	191
12 months or more Gross Unrealized Losses	0	3
Total Fair Value	2,798	8,008
Total Gross Unrealized Losses	34	31
Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises And U S Government [Member]
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	88,198	90,543
Less than 12 months Gross Unrealized Losses	314	208
12 months or more Fair Value	2,762	0
12 months or more Gross Unrealized Losses	4	0
Total Fair Value	90,960	90,543
Total Gross Unrealized Losses	318	208
Collateralized Mortgage Obligations Issued By Private Enterprise [Member]
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	0	13,595
Less than 12 months Gross Unrealized Losses	0	539
12 months or more Fair Value	35,826	44,148
12 months or more Gross Unrealized Losses	2,474	6,783
Total Fair Value	35,826	57,743
Total Gross Unrealized Losses	2,474	7,322
Collateralized Mortgage Backed Securities [Member]
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	205	5,577
Less than 12 months Gross Unrealized Losses	4	14
12 months or more Fair Value	801	1,466
12 months or more Gross Unrealized Losses	30	36
Total Fair Value	1,006	7,043
Total Gross Unrealized Losses	34	50
Equity Securities [Member]
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	5,164	5,199
Less than 12 months Gross Unrealized Losses	130	95
12 months or more Fair Value	3	2
12 months or more Gross Unrealized Losses	8	9
Total Fair Value	5,167	5,201
Total Gross Unrealized Losses	138	104
Other
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	0	0
Less than 12 months Gross Unrealized Losses	0	0
12 months or more Fair Value	0	0
12 months or more Gross Unrealized Losses	0	0
Total Fair Value	0	0
Total Gross Unrealized Losses	$ 0	$ 0